In an air conditioner and the like, various methods have been examined as a method of supplying a voltage to a compressor that smoothes lubricating action of the inside of the compressor. For example, there is a method of supplying a high-frequency low voltage to a compressor while operation is stopped during heating (see, for example, Patent Literature 1).
There is also a method of supplying a single-phase alternating current voltage having a frequency higher than a frequency during normal operation to a compressor when it is detected that an ambient temperature of an air conditioner is in a low-temperature state (see, for example Patent Literature 2).